I have migrate from Exchange 2007 to Exchange 2013. Everything seems to work fine on that side. The only litlle problems IM facing is that some emails and tasks in Outlook are long to open. When they are bigger than 2Mg it could take up to 1 minute to open. And also sometimes when I try to forward an email that has an image Embedded in it to somebody I receive an Outlook error. "Problem with the client" and the email is not sending. If I try this last operationj with OWA it's working fine.
My users are using Outlook 2010 and Outlook 2013.